1. Field
One embodiment of the present invention relates to an information processing apparatus provided with a main body which can be docked with an external apparatus, and in particular an information processing apparatus having a function of communicating with the external apparatus by radio, an information processing system also having the function, and a radio communication control method for the information processing apparatus and the system.
2. Description of the Related Art
In recent years, various kinds of portable information processing apparatuses such as notebook computers have been developed. Of those computers, some are formed such that they can be docked with an external apparatus in order to expand their functions. The external apparatus permits an option device, which can be controlled by the computer docked with the external apparatus, to be connected to the external apparatus.
In such a system, the functions of the option device connected to the external apparatus can be utilized simply by connecting the computer to the external apparatus. Accordingly, the user does not need to attach the option device to the computer, and the space for the system is not increased, since it is not necessary to use cables or the like to connect the computer to the external apparatus.
Jpn. Pat. Appln. KOKAI Publication No. 10-55231 discloses a technique in which a portable computer is placed adjacent to a docking station to communicate with the docking station (by using an infrared signal, an optical fiber or a radio signal)
In general, a computer sends a radio signal over a wide range to communicate by radio with a desired device located apart from the computer by a predetermined distance. Therefore, when the computer communicates by radio with an external apparatus connected to the computer, it also outputs a radio signal over a wide range. Therefore, there is a possibility that power for the radio communication may be wastefully consumed. Furthermore, if a number of radio communication apparatuses are present, there is a possibility that communication channels cannot be allocated to all the radio communication apparatuses. In addition, since the radio signal is transmitted over a wider range than is necessary, there is a risk that information carried by the radio signal may be intercepted.